[Tails-dev] [review'n'merge: 1.2.1] bugfix/8158-stacked-root…

Hi,

This branch fixes bugs #8152 and #8158 and is based on a patch
contributed by sanic (Thanks again!). Since I had to re-write the patch
a bit I suppose it should be review'n'merged by someone else, so please
review'n'merge into stable and devel!

As for testing, see #8158 (comment 13) for what I did.

Cheers!